 <Window xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
   xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
   Height="100" Width="300" 
   WindowStartupLocation="CenterScreen" Title="Animate String Data!">
   <StackPanel>
     <Button Name="myButton" Height="40"
             FontSize="16pt" FontFamily="Verdana" Width = "100">
      <Button.Triggers>
        <EventTrigger RoutedEvent="Button.Loaded">
          <BeginStoryboard>
            <Storyboard>
              <StringAnimationUsingKeyFrames RepeatBehavior = "Forever"
                Storyboard.TargetName="myButton" Storyboard.TargetProperty="Content"
                Duration="0:0:3">
                <DiscreteStringKeyFrame Value="" KeyTime="0:0:0" />
                <DiscreteStringKeyFrame Value="O" KeyTime="0:0:1" />
                <DiscreteStringKeyFrame Value="OK" KeyTime="0:0:1.5" />
                <DiscreteStringKeyFrame Value="OK!" KeyTime="0:0:2" />
              </StringAnimationUsingKeyFrames>
            </Storyboard>
          </BeginStoryboard>
        </EventTrigger>
      </Button.Triggers>
    </Button>
  </StackPanel>
</Window>
